Systems and methods for delivery of peritoneal dialysis (pd) solutions with integrated inter-chamber diffuser

ABSTRACT

The invention provides, in some aspects, a container system for medical solutions such as peritoneal dialysis (PD) solutions. The invention particularly features a system which includes a first compartment that contains a first medical solution, e.g., a PD osmotic agent, and a second compartment that contains a second medical solution, e.g., a PD buffer agent. The compartments maintain their respective contents separately from one another for purposes of transport, storage and/or sterilization. However, the compartments are fluidly couplable, so that their respective contents can be combined with one another, e.g., following sterilization of the agents and prior to their introduction into the patient&#39;s abdomen. To that end, a container system can include a diffuser that is disposed in a fluid pathway between the first and second compartments, e.g., to facilitate homogeneous mixing of the first and second PD agents. That diffuser is disposed within and moves relative to a structure, such as a port that defines the fluid pathway between those compartment. Thus, for example, the diffuser can comprise a body that “floats” within that pathway-defining structure and that moves from one end to the other (and/or to from points there between), depending on a direction of solution flow through the structure.

BACKGROUND OF THE INVENTION

This application is related to the following: U.S. patent application Ser. No. 12/423,627, filed Apr. 14, 2009, entitled “Systems and Methods for Delivery of Peritoneal Dialysis (PD) Solutions,” U.S. patent application Ser. No. 12/326,141, filed Dec. 2, 2008, entitled “Systems and Methods for Delivery of Peritoneal Dialysis (PD) Solutions,” U.S. patent application Ser. No. 11/829,611, filed Jul. 27, 2007, entitled “Systems and Methods for Delivery of Peritoneal Dialysis (PD) Solutions,” U.S. patent application Ser. No. 11/340,403, filed Jan. 26, 2006, entitled “Systems and Methods for Delivery of Peritoneal Dialysis (PD) Solutions,” U.S. patent application Ser. No. 11/046,667, entitled “System and Methods for Dextrose Containing Peritoneal Dialysis (PD) Solutions With Neutral PH And Reduced Glucose Degradation Product,” filed Jan. 28, 2005, the teachings of all of which applications are incorporated herein by reference.

The invention relates to peritoneal dialysis (PD). In particular, it provides containers and methods for treating peritoneal dialysis solutions that reduce glucose degradation products (GDPs).

Peritoneal dialysis (PD) is a medical procedure for removing toxins from the blood that takes advantage of the semi-permeable membrane surrounding the walls of the abdomen or peritoneal cavity. During a PD procedure, a solution is introduced into the patient's abdomen, where it remains for up to several hours, removing blood toxins via osmotic transfer through that membrane. At completion of the procedure, the solution is drained from the body along with the toxins.

An active constituent of the PD solution is an osmotic agent, such as glucose, that creates an osmotic gradient across the peritoneal membrane, allowing exchange of toxins from the blood into the peritoneal cavity, as described above. Another constituent is an electrolyte composition, such as a mixture of sodium, calcium, potassium, chlorine, magnesium, and so forth, which restores and maintains electrolyte balance in the blood. A final typical constituent is a buffering agent, such as lactate and pyruvate, which ensures that the blood pH remains at a physiological norms during the procedure.

A major problem with commercially available PD solutions is the presence of degradation products. These products, which typically arise during long-term storage or sterilization of the solutions, damage the peritoneal wall and can adversely affect proteins elsewhere in the patient's body.

Attempts to eliminate these degradation products have met some success. An example is the assignee's own U.S. Pat. No. 6,277,815, which utilizes a multi-chamber PVC or polyolefin bag to separate PD constituents during storage and sterilization. That notwithstanding, there remains a continuing need for improved containers and methods for PD solutions to reduce glucose degradation products (GDPs). Providing these is among the objects of this invention.

Another object of the invention is to provide such containers and methods as can be fabricated at low cost.

Still another object of the invention is to provide such containers and methods as can be fabricated utilizing existing materials and fabrication techniques

Still yet still another object of the invention is to provide such containers and methods as can be provided PD solutions of physiologically optimal concentrations and pH levels.

SUMMARY OF THE INVENTION

The foregoing and other objects are attained by the invention which provides, in some aspects, a container system for medical solutions such as peritoneal dialysis (PD) solutions. Such a system includes a first compartment that contains a first medical solution, e.g., a PD osmotic agent, and a second compartment that contains a second medical solution, e.g., a PD buffer agent. The compartments maintain their respective contents separately from one another for purposes of transport, storage and/or sterilization. However, the compartments are fluidly couplable, so that their respective contents can be combined with one another, e.g., following sterilization of the agents and prior to their introduction into the patient's abdomen. To that end, such a container system can include a diffuser that is integrated into a fluid pathway between the first and second compartments, e.g., to facilitate mixing of the first and second PD agents.

According to related aspects of the invention, that diffuser is disposed within and moves relative to a structure, such as a port, that defines the fluid pathway between those compartments. Thus, for example, the diffuser can comprise a body that “floats” within that pathway-defining structure and that moves from one end to the other (and/or to from points there between), e.g., depending on a direction of solution flow through the structure.

Related aspects of the invention provide a container system, e.g., as described above, in which the diffuser is enclosed within the aforesaid (port) structure, e.g., so that at extremes of its motion within the port, it does not protrude substantially (if at all) beyond an end of that structure.

Further related aspects of the invention provide a container system, e.g., as described above, in which the diffuser comprises multiple apertures to effect dispersion of PD agent flowing from one of the compartments into the other, more particularly, upon its expulsion into that other compartment.

Still further aspects of the invention provide a container system, e.g., as described above, in which one or more of the apertures comprises passages extending through a body of the diffuser, e.g., oriented along an axis parallel to a fluid flow path of the port or other pathway-defining structure. Related aspects provide such a container system in which one or more of the apertures comprise surface indentations on the body of the diffuser, again, for example, oriented along an axis parallel to a fluid flow path of the port or other pathway-defining structure.

Further related aspects of the invention provide a container system, e.g., as described above, in which the first and second compartments comprise separate chambers of a single vessel, e.g., a “multi-chamber” vessel. Thus, for example, those compartments can form separate chambers of a bag, tube or other vessel of flexible, moldable or malleable material such as PVC or other medical grade material.

In related aspects, a multi-chambered vessel as described above can be formed to permit at least one of the compartments to be manipulated, e.g., bent, twisted, squeezed and/or folded, at least partially independently of the other. Thus, for example, portions of the vessel in which the respective compartments are formed are at least partially separable from one another so that, for example, one portion can be folded and its respective compartment squeezed without substantially folding the other and squeezing its respective compartment—thus, for example, permitting the user expel liquid from one compartment into the other.

Still other aspects of the invention provide systems for delivery of PD solutions as described above in which the portion of the vessel forming the second compartment folds upon application of force to expel the PD constituent contained therein.

According to related aspects of the invention, the port or other pathway-defining structure of a container system, e.g., as described above, comprises a first frangible seal to prevent contact between the PD osmotic agent and the PD buffer agent. That seal is temporary and can be broken, e.g., by a patient, health care provider or manufacturer, to permit the agents to mix following their sterilization and prior to their introduction into the patient's abdomen.

In a related aspect, the invention provides a container system, e.g., as described above, in which a second frangible seal prevents fluid transfer between the second compartment and an outlet fluid pathway that leads, e.g., to the patient. A cover or other protective structure can be provided to deter the patient, his/her health care provider, or others, from breaking the second seal prior to the first seal. This has the benefit, for example, of ensuring mixing of the agents before their delivery to the patient.

In a related aspect of the invention, that protective structure is initially positioned in protective relation to the second seal where it inhibits the breaking of that seal. The structure includes a slot or other opening arranged to slide over at least a portion of the vessel forming the second compartment only if that vessel is at least partially folded and, thereby, to move from the initial position to a second position, where it does not protect the second seal.

In related aspects of the invention, the aforementioned slot or other opening is arranged to slide over at least the portion of the vessel forming the second compartment only after a quantity of the PD constituent originally contained therein has been expelled therefrom.

In further related aspects of the invention, the slot or other opening is arranged to slide over at least the portion of the vessel forming the second compartment only after at least 10%-30% of a quantity of the PD constituent originally contained in that compartment has been expelled therefrom.

In further related aspects of the invention, the slot or other opening is arranged to slide over at least the portion of the vessel forming the second compartment only after at least 30%-50% of a quantity of the PD constituent originally contained in that compartment has been expelled therefrom.

In further related aspects of the invention, the slot or other opening is arranged to slide over at least the portion of the vessel forming the second compartment only after at least 75% of a quantity of the PD constituent originally contained in that compartment has been expelled therefrom.

Further aspects of the invention provide a container system, e.g., as described above, in which the port or other pathway-defining structure include flanges and/or other structural elements to prevent the diffuser from obstructing flow of PD agent into, through and/or out of that pathway-defining structure. Such flanges can be positioned, for example, at an end of the inner diameter of the pathway-defining structure and can be sized and/or shaped to prevent the diffuser from advancing toward the distal end of the structure closer than an offset that ensures adequate clearance for fluid passage to/from that end of the structure.

Further aspects of the invention provide a container system, e.g., as described above, in which the port or other pathway-defining structure include tabs that flex to allow the diffuser to be inserted into the seal/port structure during assembly of the container system.

Yet still further aspects of the invention provide a container system, e.g., as described above, in which the port or other pathway-defining structure include flanges and/or other structural elements to prevent the first or second seals from obstructing flow of PD agent into, through and/or out of that pathway-defining structure. Such flanges can be positioned, for example, at ends of the pathway-defining structure and can be sized and/or shaped to prevent the diffuser from advancing toward the distal end of the structure closer than an offset that ensures adequate clearance for fluid passage into or out of the structure.

Further aspects of the invention provide a container system, e.g., as described above, in which the PD buffer agent is highly concentrated and/or highly alkaline. Thus, the buffer agent can be about 3-fold higher in concentration than the chemically “Normal” concentration for that agent, preferably 5-fold or higher, more preferably, 7-fold or higher, more preferably, 10-fold or higher, and still more preferably, 15-fold or higher. Since conventional, commercially-available PD solution buffer agents are of chemically Normal concentrations, the buffer agent according to these aspects of the invention can likewise be about 3-fold higher in concentration than conventional buffer agents, preferably 5-fold or higher, more preferably, 7-fold or higher, more preferably, 10-fold or higher, and still more preferably, 15-fold or higher. Examples of suitable PD buffer agents for use in these aspects of the invention include, but are not limited to, lactate, acetate, and pyruvate. According to related aspects of the invention, the PD buffer agent has a pH of about 8.0 to about 14.0, and, more preferably, a pH of about 9.0 to about 13 and, still more preferably, a pH of about 10.0 to about 12.0.

According to related aspects of the invention, the second compartment (in which that PD buffer agent is stored) has a small volumetric capacity relative to that of the first compartment. Likewise, the volumetric amount of PD buffer agent is small compared to that of the PD osmotic agent. Thus, for example, where the first compartment is of standard clinical use capacity (between 1-5 liters), the second compartment is sized between 5 ml-50 ml, and preferably about 7.5-37.5 ml.

In still other related aspects of the invention, the ratio of the volumetric capacity of the first to second compartments is in the range of about 20:1 to about 200:1, preferably about 50:1 to about 150:1, and preferably about 70:1 to about 140:1, preferably about 90:1 to about 120:1, and most preferably about 133:1.

According to further aspects of the invention, the PD osmotic agent is at physiological use concentrations, i.e., substantially at concentrations at which that agent will be introduced into the patient's abdomen. In related aspects of the invention, those concentrations are between 1.5%-4.25% and, more preferably, between 2.0%-4.0% and, still more preferably, between 2.0%-3.0%.

The PD osmotic agent, moreover, according to related aspects of the invention, is at a physiologically low pH, i.e., a pH below that at which that agent will be introduced into the patient's abdomen. In related aspects of the invention, those pH levels are between 1.0-6.0 and, most preferably, between 1.0-3.0. The PD osmotic agent can be, by way of non-limiting example, a sugar selected from the group consisting of glucose, dextrose, icodextrin, and fructose. In further related aspects of the invention, the first compartment can contain electrolytes, in addition to the osmotic agent.

Further aspects of the invention provide a container system, e.g., as described above, in which the first and second compartments are formed in vessels that are fabricated separately from one another. Thus, for example, the first compartment can be formed in a 1-5 liter glass container (e.g., an infusion bottle) or flexible bag (e.g., an infusion bag) made, for example, of PVC, polyolefin, polypropylene, or other medical-grade material) of the type typically used to contain and/or administer peritoneal dialysis fluids. The second compartment can be formed in separate container, such as a tube or vial of flexible, moldable or malleable material such as PVC, all by way of non-limiting example.

In related aspects, the aforementioned vessels adapted so that they can be directly or indirectly physically coupled to one another to support fluid transfer between the compartments. Thus, for example, a PVC bag in which the first compartment is formed can have a port for receiving, by fusing, bonding, interference-fit, screw-fit, or otherwise, a tube in which the first compartment is formed. Alternatively, or in addition, that port can be arranged to receive a needle-like extension, bayonet, or other adapter affixed to such a tube. By way of further example, both vessels can be adapted to receive opposing ends of a common piece of medical-grade tubing.

Further aspects of the invention provide methods for peritoneal dialysis solutions that contemplate sterilizing a PD osmotic solution contained in a first compartment, sterilizing a PD buffer agent of concentration and/or pH as described above contained in a second compartment, where the first and second compartments are not in fluid communication during the sterilization steps. The method further contemplates placing the first and second compartments in fluid communication following the sterilization step and mixing their contents with one another, prior to introducing the mixed contents into a patient's abdomen.

Still further aspects of the invention provide methods as described above in which the second compartment (in which that PD buffer agent is stored) has a small volumetric capacity relative to that of the first compartment and/or likewise, where the volumetric amount of PD buffer agent is small compared to that of the osmotic agent.

Still further aspects of the invention provide methods as described above that include breaking of a seal between the first and second compartments and, thereby, allowing their contents to mix following the sterilization stage. This can include, for example, bending and/or squeezing the vessel that includes the first compartment in order to break a frangible sealing member that separates the buffer agent from the osmotic agent.

Other aspects of the invention provide methods paralleling the operations described above.

Still other aspects of the invention provides container systems and methods as described above for other medical and non-medical solutions.

These and other aspects of the invention are evident in the drawings and in the description that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the invention may be attained by reference to the drawings, in which:

FIG. 1 depicts a system for containing a peritoneal dialysis solution according to one practice of the invention and includes a break-out portion depicting one of the vessels of that system in greater detail;

FIG. 2 depicts a sequence for sterilizing and administering a peritoneal dialysis solution according to the invention;

FIG. 3 depicts a system for containing a peritoneal dialysis solution according to a further practice of the invention and includes a break-out portion depicting one of the vessels of that system in greater detail;

FIGS. 4A-4C depict utilization of the system of FIG. 3 to mix agents of the peritoneal dialysis solution (e.g., following sterilization) and to transfer the mixed agents to the patient.

FIG. 5 is a schematic of a frangible seal.

FIG. 6 depicts a system for containing a peritoneal dialysis solution according to one practice of the invention that includes a protective member adapted to inhibit breaking of a second seal prior to breaking of a first seal.

FIGS. 7A-7E illustrate operation of the system of FIG. 6.

FIGS. 8A-8B illustrate an embodiment of the invention incorporating an alternate configuration of the second container of FIG. 6.

FIG. 9 illustrates an embodiment of the invention in which the fluid-filled second compartment defines the protective member.

FIGS. 10A-10D illustrate operation of the system of FIG. 9.

FIGS. 11A-11F illustrate configuration and use of the embodiment of FIGS. 8A-8B.

FIGS. 12A-12E depict use of a container system according to the invention that includes a diffuser in a fluid pathway between the vessels.

FIGS. 13A-13E depict a procedure for use of the container system depicted in FIGS. 12A-12E.

FIGS. 14A-14E are graphs of pH as a function of the outflow volume of the catheter of sample systems of the type shown in FIGS. 12A-12E when used with normally expected operating procedures.

FIG. 15 depicts a multi-chamber vessel for containing a peritoneal dialysis solution according to one practice of the invention.

FIGS. 16A-16F depicts a manner of use of the multi-chamber vessel of FIG. 15.

FIGS. 17A-17D depict an alternate embodiment of the multiple-chamber vessel of FIG. 15 for containing peritoneal dialysis solution according to the invention.

FIGS. 18A-18B depict capture of the diffuser and/or frangible seal in the multiple-chamber vessel of FIGS. 17A-17D.

DETAILED DESCRIPTION

FIG. 1 illustrates a container system for PD solutions according to one practice of the invention. The container system 10 has a first vessel 12 that contains, in compartment 12 a, a PD osmotic agent solution 14. A second vessel 20 contains, in compartment 20 a, PD buffer agent solution 22. The vessels 12, 20 and, more particularly, the compartments 12 a, 20 a are coupled for fluid exchange via port 18 formed in vessel 12, as shown. A temporary seal 24 is provided in the fluid-transfer path between the compartments, also as shown. This prevents contact between or mixing of the PD osmotic agent and the PD buffer agent, e.g., until after sterilization of the agents. A further temporary seal 26 is provided in a catheter 28 that leads, e.g., to the patient's peritoneal cavity (not shown), and prevents flow of PD solution, e.g., until after mixing of the sterilized agents.

Illustrated first vessel 12 is a conventional medical-grade PVC hanging “transfusion” bag, as illustrated. In other embodiments it may be of other configurations and/or comprised of other materials, such as a glass container or other flexible or non-flexible containers (of PVC, polyolefin, polypropylene, or other medical-grade material) of the type typically used to contain and/or administer peritoneal dialysis agents. The compartment 12 a is formed within the vessel 12 in the conventional manner and, in the illustrated embodiment, is of standard clinical use capacity (e.g., sized between 1-5 liters), though other sizes may be used as well. As indicated above, vessel 12 includes at least one port 18 providing a fluid-transfer path to compartment 12 a. This port can be used to transfer agents to and from the vessel 12, e.g., during manufacture at the pharmaceutical plant, during mixing of the agents, and/or during administration of the mixed agents to the patient. Other embodiments may use a greater or fewer number of ports than those illustrated and, indeed, may use no ports at all (e.g., where needles or other methods are used to add and remove agents from the compartment 12 a).

Illustrated vessel 20 is a tube-like vessel (or miniature bulb or “mini-bulb”) of PVC or other medical grade material suitable for containing at least a PD buffer agent. The illustrated vessel is semi-rigid and, therefore, suitable for squeezing or other manipulation by a patient, health care provider or manufacturer, e.g., to facilitate breaking of the seal 24, extrusion of the PD buffer agent out from compartment 20 a and into compartment 12 a, and/or mixing of the PD agents. In other embodiments, the vessel may be of other configurations and may be fabricated from other materials (e.g., rubber, polyolefin, polypropylene, and/or other medical grade materials). Moreover, the vessel need not be semi-rigid: it may be rigid or flexible, depending on how the patient, health care provider or manufacturer are expected to use it for purposes of breaking of seal 24, expelling the PD buffer agent and/or mixing of the PD agents Still further, although vessel 20 has a tube-like configuration, other embodiments may utilize vessels of different shapes. Vessel 20 can be formed by a blow molded or dipping-formed bubble in-line with the solution bag outlet. Other methods for forming the second vessel are possible also, such as formation during the tubing extrusion process (commonly called Bump tubing) or heat forming vessel 20 in pre-extruded tubing.

Illustrated vessel 20 is adapted for direct or indirect coupling with vessel 12 so as to provide a fluid transfer path between compartments 12 a, 20 a. To this end, vessel 20 has a proximal end port 25 adapted for fusing, bonding, interference-fit, screw-fit or other coupling with vessel 12, hereby, by way of its port 18, as shown in the drawing. In other embodiments, fluidic coupling between the compartments 12 a, 20 a may be attained in other ways, e.g., by needle- or bayonet-like adapters affixed to either vessel (or its respective port) for receipt by the other vessel.

Vessel 20 is likewise adapted for direct or indirect fluid transfer to the patient's peritoneal cavity. In the illustrated embodiment, this is by way of a distal port 27 adapted for fusing, bonding, interference-fit, screw-fit or other coupling with catheter 28, as shown. That catheter may lead directly to the peritoneal cavity or indirectly, e.g., by way of filters, heaters and/or other medical apparatus.

The compartment 20 a of the second vessel 20 has small volumetric capacity in comparison to that of the first vessel 12. Thus, for example, where the first compartment 12 a of the illustrated embodiment is of a capacity sized between 1-5 liters, the second compartment 20 a is sized about 5-50 ml, preferably about 7.5-37.5 ml. Thus, it will be appreciated that the ratio of volumetric capacity of the first to second compartments is about 20:1 to about 200:1, preferably about 50:1 to about 150:1, and preferably, about 70:1 to about 140:1, and most preferably about 133:1.

Seal 24 is adapted to prevent fluid transfer (or other contact) between the PD agents contained in compartments during manufacture, transport, storage and sterilization of system 10, yet, to permit such fluid transfer upon breaking of that seal 24 (e.g., by a patient, health care provider, or manufacturer) for purposes of mixing the agents following sterilization. In the illustrated embodiment, the patient, health care provider, or manufacturer need not introduce a foreign object (such as a needle) to break the seal 24. Rather, this may be accomplished by squeezing, twisting or other manipulation of vessel 20 and/or port 18. To this end, in the illustrated embodiment, the seal 24 is a frangible member disposed between the aforementioned proximal port of the vessel 20 and the port 18 and is affixed to (and/or formed integrally with) an interior fluid-transfer path of one or both of those ports.

Seal 24 can be fabricated from nylon, plastic, or other medical-grade material, and can be constructed in the manner of conventional frangible seals known in the art and commercially available in the marketplace, e.g., from medical supply manufacturers Baxter, Gambro and Qosina. One preferred seal 24 is constructed in the manner of the frangible seal commercially available from Fresenius Medical Care, e.g., as a component of its Premiere™ Plus Double Bag system. That seal is depicted in FIG. 5.

Referring to the drawing, illustrated seal 24 comprises an elongate member having a head portion 24 a and a tail portion 24 b, as shown. The latter comprises a main body 24 c and flanges 24 d which, together, clamp the distal end of port 18 and the proximal end of vessel 20 (as shown), thus, providing physical coupling between the vessels 12 and 20. The tail portion 24 b has a central throughway which permits fluid coupling between compartments 12 a, 20 a, when frangible bond 24 e is broken, as discussed below.

The head portion 24 a, shown here of generally mushroom cap shape, is coupled to tail portion 24 b by frangible bond 24 e. Head portion 24 a does not include a fluid throughway and, hence, prevents fluid from flowing between compartments 12 a, 20 a through tail portion 24 b so long as bond 24 e remains intact. That bond 24 e, which may be formed by ultrasonic welding, adhesives, interference fit, fusing, integral molding, or otherwise, breaks upon bending or other manipulation of the seal 24 (e.g., by patient, health care provider, or manufacturer), thereby permitting such flow.

Those skilled in the art will appreciate that FIG. 5 depicts an example of a type of seal which can be used in practice of the invention and that seals of other configurations (frangible or otherwise) which prevent undesired contact between the PD agents, yet, permit such contact to be established by the patient, health care provider, or manufacturer, may be used instead or in addition.

With reference back to FIG. 1, seal 26 is adapted to prevent fluid transfer to the patient prior to both sterilization and mixing of the PD agents. As above, the patient, health care provider, or manufacturer does not need to introduce a foreign object (such as a needle) to break seal 26 but, rather, may be accomplish this by squeezing, twisting or other manipulation of vessel 20, the distal port thereof and/or catheter 28. To this end, as above, the seal 26 of the illustrated embodiment is a frangible member disposed between the aforementioned distal port of the vessel 20 and the catheter and affixed to (and/or formed integrally with) an interior fluid-transfer path of one or both of those. The seal 26, too, can be fabricated from nylon, plastic, or other medical-grade material, and it can be formed in the configurations discussed above in connection with seal 24 (and shown, for example, in FIG. 5).

In the embodiment of FIG. 1, the focus and/or type of manipulation required to break seal 26 differs from that required to break seal 24. This prevents both seals 24, 26 from being unintentionally broken at the same time and, thus, helps insure that the sterilized fluids are mixed prior to their being transferred to the patient. To facilitate this, the seals 24, 26 can be colored differently to alert and remind the user of the proper order in which they are to be broken. Those skilled in the art will appreciate, of course, that coloration can be used in connection with other elements of the system 10, as well.

Referring to FIG. 6, additional structure can be provided to further insure that the seals 24, 26 are broken in the proper order and, therefore, to prevent fluid transfer to the catheter 28 (and any downstream equipment) prior to sterilization and mixing of the PD agents. That drawing depicts container system 50 of the same general configuration as container system 10 of FIG. 1 (as indicated by like reference numerals), albeit including a protective member in the form of cover 52 that slides from an initial position, wherein it protects seal 26 from manipulation, to a second position, wherein it permits that seal to be broken. FIGS. 6 and 7A-7C show cover 52 in the initial position. FIG. 7D-7E show the cover 52 in the second position.

Referring to FIG. 6, cover 52 is shown in its initial position, disposed in protective relation to seal 26. In this regard, cover 52 is, more particularly,

-   -   (a) disposed in surrounding relation to the distal port of         vessel 20, the catheter 28 and/or such other structures of         system 50 in vicinity of seal 26 that (as discussed above) the         patient, health care provider, or other user manipulates in         order to break seal 26, and     -   (b) thereby prevents (or otherwise inhibits) breaking of seal 26         prior to breaking of seal 24.

The cover 52, which can comprise nylon, plastic, or other material (medical-grade or otherwise), preferably, in a rigid or semi-rigid formulation, includes an annular or other internal passageway 54 in which seal 26, the distal port of vessel 20, and/or proximal portion of catheter 28 are initially disposed, as shown in the drawing. The internal passageway extends from a distal end 56 to a proximal end 58 and, in the illustrated embodiment, has an internal diameter that can, though need not, vary therebetween, e.g., as shown.

An inner diameter of the passageway 54, e.g., at the proximal end 58, is sized and shaped to inhibit movement of cover 52 in a distal-to-proximal direction (e.g., “upward” in the drawing) prior to breaking of seal 24, e.g., when vessel 20 contains its post-manufacture complement of PD buffer agent solution 22 (and/or other liquids, gasses or solids). More particularly, the inner diameter of that passageway at the proximal end 58 is smaller than an outer diameter of vessel 20 prior to breaking of seal 24 and any of (a) at least some reduction in that outer diameter (via expulsion of a post-manufacture complement of solution 22 and/or other liquids, gasses or solids) from vessel 20—and, preferably, at least 10%-30% and, still more preferably, at least 30%-50% and, yet still more preferably, at least 50%—of such reduction, and/or (b) a decrease in resistance to such reduction.

The passageway 54 can have a larger inner diameter at the distal end 56 than at the proximal end 58, as shown in the drawing. This can help prevent bending of catheter 28 (e.g., at the point it emerges from end 56) and possible premature breakage of seal 26 during transport, storage and initial use.

Proximal-to-distal movement of cover 52 can also be constrained by a suitable stop—here, for example, a flange 57 at the proximal end of catheter 28 and/or distal end of vessel 20 sized larger than the inner diameter passageway 54 at its proximal end 58 but smaller than the inner diameter of that passageway at its distal end 56. As shown in the drawing, the flange permits distal-to-proximal movement of the cover 52, but inhibits its proximal-to-distal movement.

In some embodiments of the invention, the cover 52, as well as the seals 24, 26, are colored differently to alert and remind the user of the proper order in which they are to be broken. Those skilled in the art will appreciate, of course, that coloration can be used in connection with other elements of the system 10, as well.

FIGS. 7A-7E depict use of cover 52—initially protecting, then, permitting manipulation (and breaking) of seal 26.

Initially, as shown in FIG. 7A, seals 24, 26 are unbroken and compartment 20 a contains its post-manufacture complement of buffer agent 22 (and/or other gasses, fluids, solids). Consistent with the discussion above, with the compartment 20 in this condition, the size differential between outer diameter of vessel 20 and inner diameter of passageway 54 inhibits distal-to-proximal (e.g., “upward”) movement of cover 52.

Referring to FIGS. 7B-7C, the cover 52 remains in its initial position while the user breaks seal 24 (e.g., by bending the proximal end of vessel 20 relative to port 18) and compresses vessel 20 in order to expel buffer agent 22 for mixing with osmotic agent 14.

Referring to FIG. 7D, the user slides the cover in the distal-to-proximal direction over the vessel 20 and away from the seal 26, once the seal 24 has been broken and the outer diameter of vessel 20 has been reduced (or, at least, resistance to such reduction has been eliminated). With the cover 52 moved, the user can more readily manipulate the distal end of vessel 20 and/or the proximal end of catheter 28 in order to break seal 26. See FIG. 7E.

Those skilled in the art will appreciate that cover 52 and/or vessel 20 can have shapes other than those shown in FIGS. 6 and 7, yet, operate in the manner discussed above in connection therewith.

One such alternate configuration is depicted in FIGS. 8A-8B, which shows in front- and side-views, respectively, a vessel 21 having the same function as element 20, above—albeit shaped with a central portion that is elongate in the transverse direction and that generally defines an oval shape, as shown. The vessel 21 of the illustrated embodiment is formed from halves (or other portions) of PVC, polyolefin or other medical-grade flexible or semi-rigid material that are glued, ultrasonically welded or otherwise fused along an edge 21A in the conventional manner known in the art (although the vessel can be formed—from a single portion or multiple portions—in other ways).

The cover 53 of FIGS. 8A-8B functions in the same manner as cover 52, above, albeit it includes a slot 53A that skirts the edge 21A when the cover 53 is slid in the distal-to-proximal direction over the vessel 21 and away from the seal 26 (once the seal 24 has been broken and the volume of vessel 21 has been reduced).

In comparison to the configuration of FIGS. 6-7, that shown in FIGS. 8A-8B requires more complete reduction in outer diameter (via expulsion of a post-manufacture complement of solution 22 and/or other liquids, gasses or solids) from vessel 21 in order to permit distal-to-proximal movement of cover 53.

FIGS. 11A-11F depict a configuration and use of vessel 21 to facilitate expulsion of the post-manufacture complement of solution 22 (and/or other liquids, gasses or solids) into vessel 12 (not shown in these drawings) for mixing with solution 14 prior to introduction of the resulting solution into the patient's abdomen. Such expulsion is graphically depicted in FIGS. 11C-11F by the arrow labeled 22. As with vessel 21 of FIGS. 8A-8B, vessel 21 of FIGS. 11A-11F serves a same function as vessel 20, described earlier, and may be used (e.g., preferably, along with cover 53) in place of vessel 20 (or alternates therefore, e.g., vessel 42, discussed elsewhere herein) in systems according to the invention.

As above, the vessel 21 of FIGS. 11A-11F has a central portion that is elongate in the transverse direction and that generally defines an oval shape. And, as above, it is formed from halves (or other portions) of PVC, polyolefin or other medical-grade flexible or semi-rigid material that are glued, ultrasonically welded or otherwise fused along an edge 21A in the conventional manner known in the art (although the vessel can be formed—from a single portion or multiple portions—in other ways).

Preferably, the vessel 21 of FIGS. 11A-11F is formed to facilitate folding of its halves 21B, 21C when the vessel is squeezed, e.g., by the patient, health care provider or otherwise, following breakage of seal 24. This is graphically depicted in steps 11B showing breaking of the seal 24 (as indicated by force arrows FB), and 11C-11E showing folding of the halves 21B, 21C when squeezed (as indicated by force arrows F_(S)).

Such folding can be facilitated, by way of non-limiting example, by pre-creasing vessel 21 in a central region 21D, by reducing a cross-section of the vessel 21 in that region 21D, or otherwise. Indeed, in the illustrated embodiment, such folding is facilitated, at least in part, by the proximal and distal ports of the vessel 21, the affixation of which in vicinity of region 21D provide an axis about which halves 21B, 21C tend to naturally bend.

The cover 53 of FIGS. 11A-11F functions in the same manner as cover 53 of FIGS. 8A-8B. Albeit, slot 53A of the cover of FIGS. 11A-11F is positioned, sized and shaped to inhibit movement of the cover in a distal-to-proximal direction prior to breaking of seal 24 and expulsion from vessel 21 of a post-manufacture complement of PD buffer agent solution 22 (and/or other liquids, gasses or solids). More particularly, the slot is positioned so that it (and, consequently, cover 53 itself) cannot be slid in the distal-to-proximal direction until both sides 21B, 21C are aligned with the slot. Since only one such slot is provided in the illustrated embodiment—generally, aligned normal to the plane of the vessel 21 (as shown in the drawings)—this necessitates squeezing the sides 21B, 21C together (in the manner of butterfly wings) or otherwise folding the vessel 21 at least partially and, preferably, substantially.

Moreover, the slot 53A is sized and shaped to prevent such sliding until a cross-section of the region of sides 21B, 21C over which it (slot 53A) slides is reduced, i.e., via squeezing and expulsion of solution 22 (and/or other liquids, gasses or solids) from vessel 21—preferably, by at least 10%-30% volumetrically and, still more preferably, at least 30%-50% volumetrically and, yet still more preferably, at least 75% volumetrically and, yet, still more preferably, substantially all of that solution. This is graphically depicted in step 11F, showing repositioning of the cover 53 via a sliding force, as indicated by arrow F_(L). As evident in the drawing, the cover 53 of the illustrated embodiment does not cover the entire vessel 21 when repositioned but, rather, only the central portion: the outer “wings” of sides 21B, 21C remain outside. Of course, other embodiments may vary in this regard.

In some embodiments, slot 53A has rails, flats or other structures that effect further squeezing of the halves 21B, 21C and consequent expulsion of solution 22 (and/or other liquids, gasses or solids) therefrom when that cover is slid in the distal-to-proximal direction over those halves.

The internal passageway of the cover 53 of FIGS. 11A-11F (like passageway 54, discussed above) can be sized analogously to slot 53A, i.e., to inhibit movement of the cover in a distal-to-proximal direction prior to breaking of seal 24 and reduction in that an outer diameter of a central region of vessel 21 via squeezing and expulsion of a post-manufacture complement of solution 22 (and/or other liquids, gasses or solids) from vessel 21. And, as discussed earlier, the internal passageway of the cover 53 of FIGS. 11A-11F can have a larger inner diameter at the distal end than at the proximal end, e.g., to help prevent bending of catheter 28 and possible premature breakage of seal 26. And, as above, proximal-to-distal movement of that cover 53 can be constrained by a suitable stop and/or relative sizing of the inner diameter of the internal passageway of the cover.

Of course, those skilled in the art will appreciate that the slot (or other opening) 53A and inner passageway of cover 53 of FIGS. 11A-11F can be aligned, shaped and sized otherwise (and, indeed, that multiple slots could be provided on cover 53A) in accord with the teachings hereof.

In some embodiments, the seal 24, the vessel 21, and the cover 53 are colored differently to alert and remind the user of the proper order in which they are to be utilized. Thus, for example, the seal 24 can be colored red; the cover 53 can be colored white; and, the seal 26 can be colored blue. This red-white-blue combination can be effective in reminding patients or health care providers in locales where those colors have memorable significance (e.g., in the United States or France) that the seal 24 (red) is to be broken, first; the cover 53 (white) is to be slid, next (after squeezing out the contents of vessel 21); and, that the seal 26 (blue) is to be broken, last. Of course other color combinations or visual indicia (e.g., lettering, numbering or other symbology) may be used instead or in addition in other locales and/or among other patients or health care provider.

Preferably, the vessel 21 of FIGS. 11A-11F is formed to facilitate folding of its halves 21B, 21C when the vessel is squeezed, e.g., by the patient, health care provider or otherwise, following breakage of seal 24. This is graphically depicted in steps 11B showing breaking of the seal 24 (as indicated by force arrows F_(B)), and 11C-11E showing folding of the halves 21B, 21C when squeezed (as indicated by force arrows F_(S)).

Referring now to FIGS. 15 and 16A-16F, there is shown an alternate arrangement of the container system of FIGS. 1 and 11A-11F, here, with the PD agent-containing compartments 12 a, 20 a formed in a single vessel, e.g., a dual compartment bag or, more generally, a multi-chamber vessel. Such a container system is advantageous, for example, insofar as it facilitates handling during manufacture and shipping, yet, affords the patient, health care provider or other user the other benefits of the systems described herein. An understanding of the embodiment of FIGS. 15, 16A-16F may be appreciated by study of that drawing and the text that follows in view of the discussion elsewhere herein. In these drawings, use of reference numerals like those referred to previously (or elsewhere herein) indicates like structure and functionality, albeit as adapted for use with the embodiment of that drawing.

The container 72 shown FIG. 15 includes two portions: one (labelled 12′) that embodies the overall structure and functionality of vessel 12 and that includes compartment 12 a for PD osmotic agent solution 14; the other (labelled 21′), that embodies the overall structure and functionality of vessel 21 and that includes compartment 20 a for PD buffer agent solution 22. In practice, vessels 12 and 21 as discussed above can be fabricated separately and assembled together to form a single vessel 72 (e.g., in a configuration as shown in FIG. 15) with compartments 12 a, 20 a. Thus, for example, vessel 21 can be shaped with a central portion that is elongate in the transverse direction (or otherwise), as shown, and vessel 21 can be generally rectangular (or otherwise), as shown, with a “cut-out” to fit, mate with, or otherwise accommodate vessel 12, e.g., as shown. Preferably, however, vessel 72 is directly formed (e.g., from sheets or webs of PVC or other suitable material) to incorporate portions 12′ and 21′ and their respective chambers 12 a and 20 a, as well as one or more of the additional elements shown in the drawing and/or discussed below. Such fabrication is detailed in the sections that follow.

Illustrated vessel 72 can be fabricated from medical-grade PVC, e.g., in the manner of a hanging “transfusion” bag, as illustrated, though it may be of other configurations and/or comprised of other materials, such as flexible polyolefin or other medical-grade materials suitable used to contain and/or administer peritoneal dialysis agents. The illustrated embodiment is sized for large capacity, e.g., delivery of 6 liters or above of PD solution, though, it can be sized for standard clinical use capacities (e.g., sized between 1-5 liters) as well. The compartments 12 a, 20 a are proportioned as discussed above, i.e., such that compartment 20 a is of small volumetric capacity in comparison to that compartment 12 a. Thus, for example, where the first compartment 12 a of the illustrated embodiment is of a capacity sized between 1-5 (or 6) liters, the second compartment 20 a is sized about 5-50 ml (or 60 ml), preferably about 7.5-37.5 ml (or 45 ml). Thus, it will be appreciated that the ratio of volumetric capacity of the first to second compartments is about 20:1 to about 200:1, preferably about 50:1 to about 150:1, and preferably, about 70:1 to about 140:1, and most preferably about 133:1. Of course, it will be appreciated that the vessel and its respective compartments 12 a, 20 a can be sized otherwise for delivery of even larger and smaller amounts of PD solution.

The compartments 12 a, 20 a are coupled for fluid exchange via port 18 (e.g., an aperture or tubing) that defines a fluid transfer path. In the embodiment of FIG. 15, the port 18 is disposed internally to one or more of the compartments 12 a, 20 a—here, compartment 12 a, as shown. The port 18 can be formed integrally with vessel 72 and/or one of its constituent portions 12′ and 21′. Alternatively, or in addition, coupling between that port and the vessel (and/or portions 12′, 21′) can be provided via fusing, bonding, interference-fit, screw-fit or other coupling mechanisms. As above, fluidic coupling between the compartments 12 a, 20 a may be attained in other ways, e.g., by needle- or bayonet-like adapters affixed to either vessel (or its respective port) for receipt by the other vessel. Regardless, the port 18 (or other fluidic coupling) can incorporate a diffuser 18 a as discussed below, e.g., in connection with FIGS. 12A-12E.

Illustrated vessel 72 includes additional ports, as well. Thus, it includes port 19, which can be used to transfer agents to and from the compartment 12 a, e.g., during manufacture at the pharmaceutical plant, during mixing of the agents, and/or during administration of the mixed agents to the patient. It also includes port 27, disposed as shown, that provides a direct fluid outlet from chamber 20 a and that is coupled to catheter 28 at a junction which is obscured in the drawing by cover 53. Such coupling can be provided by fusing, bonding, interference-fit, screw-fit or other mechanisms known in the art. Other embodiments may use a greater or fewer number of ports than those illustrated and, indeed, may use no ports at all (e.g., where needles or other methods are used to add and remove agents from the compartment 12 a).

As above, a temporary seal 24 is provided in the fluid-transfer path defined by port 18. This prevents contact between or mixing of the PD osmotic agent and the PD buffer agent, e.g., until after sterilization of the agents. Also as above (see, for example, FIGS. 11A-11F and the accompanying text), a further temporary seal 26 (here, obscured by cover 53) is provided in catheter 28 that leads, e.g., to the patient's peritoneal cavity (not shown), and prevents flow of PD solution, e.g., until after mixing of the sterilized agents. The seals 24, 26 may be constructed and fabricated as discussed above, for example, in connection with FIGS. 1 and 5. In some embodiments, catheter 28 includes a connector for downstream apparatus, such as a PD tubing set, a peritoneal infusion port, or otherwise. One preferred such connector is the Safe-Lock Connector™ commercially available from the assignee hereof. In embodiments utilizing that connector, or the like, the seal 26 may comprise a frangible element integral thereto.

Such an embodiment is shown in FIG. 7D, in which a Safe-Lock Connector™ connector provides fluid and mechanical coupling between port 27 and catheter 28. In this embodiment, the seal 26 forms part of the connector and can be formed as discussed above—albeit, in the illustrated embodiment, oriented in the reverse direction (proximally-to-distally) as shown. As above, a cover 53 that includes slot 53 a protects seal 26′ from manipulation before it is slid over sides of the folded compartment 21.

As with the embodiment discussed in connection with FIGS. 11A-11F, cover 53 is slotted, and it slides from an initial (distal) position, wherein it protects seal 26 from manipulation, to a second (proximal) position, wherein it permits that seal to be broken. In the embodiment of FIG. 15, the slot 53A skirts over edge 21A of the portion 21′ that forms the second chamber 20 a, when the cover 53 is slid in the distal-to-proximal direction over that portion of vessel 72 and away from the seal 26 (once the seal 24 has been broken and the volume of vessel 21 has been reduced). Cover 53 and slot 53 a are sized and positioned to require that a specified volume of solution 22 and/or other liquids, gasses or solids be expelled from cavity 20A and its outer diameter be corresponding reduced in order to permit distal-to-proximal movement of cover 53.

In this regard, portion 21′ of illustrated vessel 72 is formed to facilitate folding of halves 21B, 21C of portion 21′ when it is squeezed, e.g., by the patient, health care provider or other user, following breakage of seal 24. This is graphically depicted in FIG. 16B showing breaking of the seal 24 (as indicated by force arrows FB), and 16C-16E showing folding of the halves 21B, 21C when squeezed (as indicated by force arrows FS).

As above, such folding can be facilitated, by way of non-limiting example, by pre-creasing portion 21′ in a central region 21D, by reducing a cross-section of the portion 21′ in that region 21D, or otherwise. Indeed, in the illustrated embodiment, such folding is facilitated, at least in part, by the ports 18, 27, the affixation of which in vicinity of region 21D provide an axis about which halves 21B, 21C tend to naturally bend.

The cover 53 of the embodiment shown in FIGS. 15 and 16A-16F functions in the same manner as cover 53 of FIGS. 11A-11F. Thus, for example, slot 53A of the cover of FIGS. 15 and 16A-16F cannot be slid in the distal-to-proximal direction until both sides 21B, 21C are aligned with the slot. Since only one such slot is provided in the illustrated embodiment—generally, aligned normal to the plane of the portion 21′ (as shown in the drawings)—this necessitates squeezing the sides 21B, 21C together (in the manner of butterfly wings) or otherwise folding the vessel 21 at least partially and, preferably, substantially.

As noted above, in some embodiments vessel 72 is directly fabricated with portions 12′ and 21′ and their respective chambers 12 a and 20 a. By way of example, the vessel 72 can be fabricated from two layers (or a single folded layer) of PVC, flexible polyolefin or other suitable sheet or web material that is cut, formed and ultrasonically welded, glued or otherwise assembled to form a vessel of the configuration shown in FIGS. 15 and 16A-16F. Ports 18 (including diffuser 18) and 27 can be fashioned simultaneously and/or incorporated into the vessel during such assembly.

In the illustrated embodiment, the vessel 72 is fabricated such that portions 12′ and 21′ are attached to one another (or substantially so) for purposes of manufacture and shipping, yet, can be partially separated from one another, e.g., by the patient, health care provider or other use prior to mixing of the PD solution. Such partial separation permits at least one of the compartments 12 a, 20 a and, preferably, compartment 20 a, to be manipulated, e.g., bent, twisted, squeezed and/or folded, at least partially independently of the other compartment 12 a, e.g., in the manner shown in FIGS. 16B-16F. Thus, for example, as shown in those drawings, portion 21′ can be separated from portion 12′ so that, for example, it can be squeezed, folded and the contents 22 of its respective compartment 20 a expelled into compartment 12 a without substantially folding portion 12′ and squeezing its respective compartment 12 a.

To this end, during fabrication of vessel 72, the PVC, flexible polyolefin or other fabrication material is perforated in one or more regions 74 between the portions 12′, 21. Prior to use, those perforations can be torn by the patient, health care provider to partially separate those portions from one another—and, more specifically, for example, to permit separation of the type shown in FIGS. 16B-16F—and to facilitate independent manipulation of their respective compartments as also shown there. In lieu of (or addition to) perforations, the portions can be cut (or otherwise separated) from one another in the region(s) 74 and tacked ultrasonically, or otherwise, to like affect. By leaving the perforations or tack-welds unbroken until use, processing and handling of the vessel 72 is facilitate during manufacture and shipping.

FIGS. 12A-12E depict a container system 10 in which port 18 of vessel 12 includes a diffuser 18 a for facilitating mixing of solution 22 (and/or other liquids, gasses or solids of vessel 21) with solution 14 (of vessel 12). The diffuser 18 a is shown in use with a system 10 that includes a vessel 12 of the type shown in FIGS. 1, 3, 4, 6, 9, and a vessel 21 and cover 53 of the types disclosed in FIGS. 11A-11F; however, it will be appreciated that it the diffuser 18 a can be utilized in connection with the other vessels and/or configurations shown and/or discussed herein.

Referring to FIG. 12A, the diffuser 18 a of the illustrated embodiment comprises a cap—here, of a generally elongated shape, but of other shapes in other embodiments—having a proximal end that is disposed within compartment 12A and that includes multiple inlet/outlet apertures 18B. A distal end of the diffuser cap is coupled to and/or comprises tubing (or other structure) defining port 18, which, as noted above, provides for fluid coupling between the vessels 12 and 21.

Three such apertures 18B are shown on the proximal end of the illustrated diffuser 18 a, though, other pluralities of apertures may be used in other embodiments, e.g., two apertures, four apertures, five apertures, and so forth. And, while apertures 18B are disposed in the illustrated embodiment at the tip of the proximal end of the diffuser 18 a, in other embodiments they may be disposed elsewhere on diffuser 18 a in fluid communication with compartment 12A

Illustrated apertures 18B are in fluid communication with an internal channel 18C that extends to the distal end of diffuser 18 a and that supports fluid coupling between vessels 12, 21, as shown. In the illustrated embodiment, two of the three apertures 18B extend from the channel 18C at an angle Ω, while one of the apertures is in line with the channel 18C, all as shown. As a result, diffuser 18 a of the illustrated embodiment causes solution 22 that is expelled into vessel 12 to disperse with an angular dispersion of 2Ω into solution 14, though the diffuser of other embodiments may effect other angular dispersions.

The angle Ω of the illustrated embodiment is in the range 20°-70° (with a resulting angular dispersion 2Ω in the range 40°-140°) and, more preferably 30°-60° (with a resulting angular dispersion 2Ω in the range 60°-120°) and, still more preferably, about 25° (with a resulting angular dispersion 2Ω of about 50°), as shown. In other embodiments, other angular ranges may be used depending on the location of the proximal tip of diffuser 18 a within compartment 12A, the size of that compartment, the characteristics of the fluids being mixed, and so forth. Although the apertures are disposed symmetrically about an axis in the illustrated embodiment, other embodiments may forego such symmetry.

Diffuser 18A may comprises nylon, plastic, or other medical-grade material (and, preferably, such medical materials as do not fuse to PVC during heat sterilization). In the illustrated embodiment, diffuser 18 a is fabricated from polycarbonate and is the same material as used in frangible members (e.g., 62, 64) discussed elsewhere herein. In other embodiments, diffuser 18 a is fabricated from polyvinylchloride (PVC) and is the same material as used for the catheter 28 and other ports and/or tubing that comprise system 10. The apertures 18C of the illustrated embodiment are preferably 1.0 to 1.5 mm in diameter, though other embodiments may use apertures of different and/or varying sizes, e.g., depending on the characteristics of the fluids being mixed and other factors indicated above, all by way of example.

Diffuser 18A facilitates mixing of solution 22 (and/or other liquids, gasses or solids in vessel 21) with solution 14 when the patient or health care provider squeezes vessel 21 in the manner shown in FIGS. 11C-11F. This is graphically depicted in steps 12B-12D showing expulsion of fluid 22 (as indicated by arrows 22) when container 21 is squeezed (as indicated by force arrows F_(S)) and cover 53 is slid (as indicated by force arrow F_(L)).

Diffuser 18A further facilitates mixing of those solutions, following breakage of seal 26, when the combined PD solution is expelled into the catheter 28 (and any downstream equipment) for introduction to a patient. This is graphically depicted in step 12E showing expulsion (e.g., under the force of gravity and/or manipulation of vessel 12) of the combined solutions 14, 22 from the vessels 12 and 21, and exit via the catheter 28 (all as indicated by the unlabeled arrows).

The configurations shown in FIGS. 11A-11F and 12A-12E may be used in connection with the PD osmotic agents, PD buffer solutions and other PD components discussed below. In this regard, it will be appreciated that, consistent with the remarks above, vessel 21 may be used (e.g., along with cover 53 or alternates therefor) in place of vessel 20 (or alternates therefor, e.g., vessel 42) discussed below and elsewhere herein.

Advantages of the configurations shown in FIGS. 11A-11F and 12A-12E include that they permit the solutions 14 and 22 to be more readily combined following expulsion of solution 22 into vessel 12, e.g., necessitating limited manipulation by the patient or health care provider in order to assure an acceptable mix of PD solution that lacks pH extremes and is an appropriate range for introduction to the patient. In this regard, for example, the diffuser 18 a facilitates mixing PD solutions of different densities and/or viscosities—and, particularly, by way of non-limiting example, a PD buffer solution 22 that has density and/or viscosity greater than that of the PD osmotic agent 14—to be mixed quickly and homogeneously, with minimal effort. An advantage of the vessel 21 of FIGS. 11A is that squeezable folding of its sides 21B, 21C (as detailed above) increases infusion pressure of solution 22 for better mixing in vessel 12. It also better increases chances for complete infusion of solution 22.

In this context a procedure for use of system 10 as shown in FIGS. 12A-12E is shown in FIGS. 13A-13F. The system of FIGS. 13A-13F, additionally includes a drain bag 23, which can be supplied with the system 10 for use in draining spent PD solution from the patient.

Referring to FIG. 13A, prior to use of the system 10, the patient or health care provider inspects and familiarizes himself/herself with vessels 12, 21, seals 24, 26 and cover 53.

Referring to FIG. 13B, the patient or health care provider next breaks the seal 24 (which, as noted above, can be differentially colored red or otherwise in some embodiments) and, then, folds the vessel 21 in half, squeezing firmly until the solution 22 originally contained in the vessel 21 is expelled into solution 14 of vessel 12.

Referring to FIG. 13C, the patient or health care provider next presses on vessel 12 in order to push solution back into vessel 21. In some embodiments, the steps shown in FIGS. 13B and 13C are carried out three times to facilitate thoroughly “washing” solution 22 from vessel 21.

Referring to FIG. 13D, the patient or health care provider next inverts the system 10 (and, significantly, vessel 12) to facilitate still more thorough mixing of the solutions 22, 44. In some embodiments, the step shown in FIG. 13D is carried out three times to facilitate thorough mixing of the solutions 14, 22.

Referring to FIG. 13E, the patient or health care provider next folds vessel 21 in half and slides the cover 53 (which, as noted above, can be differentially colored white or otherwise in some embodiments) up over the central portion of the vessel 21 until the seal 26 (which, as noted above, can be differentially colored blue or otherwise in some embodiments) is exposed where the tubing comprising catheter 28 is attached.

Referring to FIG. 13F, the patient or health care provider next grips the cover 53 (which is now repositioned over at least a portion of vessel 21) and grips the seal 26 with the other hand and bends to break the seal 26, thereby, opening a fluid pathway for outflow of the combined solutions 14, 22 (e.g., under gravity feed as effected by hanging system 10 and, significantly, vessel 12 vertically) via catheter 28 to the patient.

Of course, it will be appreciated that system 10 of FIGS. 12A-12E, as well of the other systems described herein, may be utilized with procedures other than those in FIGS. 13A-13F, as discussed more fully below. FIGS. 14A-14F are graphs depicting pH as a function of time of the outflow of catheter 28 for such alternate procedures for sample system(s) of the type shown in FIGS. 12A-12E when used with normally expected operating procedures (e.g., by way of non-limiting example, where vessel 21 is squeezed with at least a nominal squeezing force sufficient to achieve a fluid pressure of about 8 psi).

By way of non-limiting example, in one preferred such alternate procedure the steps shown in FIGS. 13B and 13C are carried out two times (rather than three times), and the step shown in FIG. 13D is carried out one time (rather than two times). A graph of pH as a function of time of the outflow volume of catheter 28 for sample system(s) of 5 L capacity of the type shown in FIGS. 12A-12E using this procedure is presented in FIG. 14A. In the sample system(s), the initial solution 14 in vessel 12 comprised dextrose, calcium chloride, magnesium chloride, and sodium chloride at pH 2.6-3.2, while the initial solution 22 in vessel 21 comprised sodium lactate and sodium bicarbonate at pH 9.2-9.4. By way of further non-limiting example, in another such alternate procedure the steps shown in FIGS. 13B and 13C were carried out two times with only nominal squeezing forces exerted on the vessel 21; inverting step shown in FIG. 13D was not carried out. A graph of pH as a function of the outflow volume of catheter 28 for sample system(s) of 5 L capacity of the type shown in FIGS. 12A-12E using this procedure, with a nominal squeezing force of about 8 psi, is presented in FIG. 14B; that for a nominal squeezing force of about 15 psi is presented in FIG. 14C. The sample system(s) were as describe in the preceding example.

By way of further non-limiting example, in another such alternate procedure the step shown in FIG. 13B was carried out one time with nominal squeezing forces exerted on vessel 21; the step shown in FIG. 13C was not carried out; and, the inverting step shown in FIG. 13D was not carried out. A graph of pH as a function of time of the outflow volume of catheter 28 for sample system(s) of 5 L capacity of the type shown in FIGS. 12A-12E using this procedure is presented in FIG. 14D. The sample system(s) were as describe in the preceding example.

By way of further non-limiting example, in another such alternate procedure the step shown in FIG. 13B was carried out one time with low pressure exerted on vessel 21; the step shown in FIG. 13C was not carried out; and, the inverting step shown in FIG. 13D was carried out one time. A graph of pH as a function of the outflow volume of catheter 28 for sample system(s) of 5 L capacity of the type shown in FIGS. 12A-12E prepared using this procedure is presented in FIG. 14E. The sample system(s) were as describe in the preceding example.

Referring now to FIGS. 17A-17D and 18A-18B, there is shown an alternate embodiment of the container system of FIGS. 15 and 16A-16F, here, with a port 18′ that is configured to facilitate fluid flow to and from the PD agent-containing compartments 12 a, 20 a after breakage of the seals 24′ and/or 26′. Such a container system is advantageous, for example, insofar as it, in addition to facilitating handling during manufacture and shipping, affords the patient, health care provider or other user improved operation when the contents of the respective compartments are mixed and introduced into a patient's abdomen. An understanding of the embodiment of FIGS. 17A-17D and 18A-18B may be appreciated by study of those drawings and the text that follows in view of the discussion elsewhere herein. Use of reference numerals (and “primed” variants thereof) like those referred to previously (or elsewhere herein) indicates like structure and functionality, albeit as adapted for use with the embodiment of the instant drawings.

Like the container 72 discussed above in connection with FIG. 15, the container 72′ shown FIG. 17 a includes two portions: one (labelled 12′) that embodies the overall structure and functionality of vessel 12 and that includes compartment 12 a for PD osmotic agent solution 14; the other (labelled 21′), that embodies the overall structure and functionality of vessel 21 and that includes compartment 20 a for PD buffer agent solution 22. The container 72 of FIG. 17 a and its respective components (e.g., portions 12′, 21′, compartments 12 a, 20 a, ports 18, 19, temporary seals 24′, 26, and cover 53) can be shaped, fabricated, sized, coupled, constructed and operated in the manner of container 72 (and its respective components) of FIG. 15, as adapted in accord with the teachings of FIGS. 17A-17D and 18A-18B and the sections that follow. In the discussion that follows the designations 12′ and 12 a are used interchangeably (unless otherwise evident from context) to refer to compartment 12 a. This is likewise true of 21′ and 20 a vis-a-vis compartment 20 a.

Although the diffuser 18 a of other embodiments shown herein comprises a cap on a proximal end of port 18, the diffuser 18 a′ of the embodiment shown in FIGS. 17A, 17B comprises an apertured body that is disposed within port 18 and, more particularly, within the fluid transfer path 18 d defined along an inner diameter of the port, as shown in the drawings.

In the illustrated embodiment, the diffuser 18 a′ moves relative to the port 18. More particularly, it “floats” within the port 18—that is, it moves within the port 18 to and/or from the proximal and distal ends (and/or points there between) as it becomes entrained in the flow through the port. Thus, for example, it moves to a proximal end of port 18′—e.g., as solution 22 (and/or other liquids, gasses or solids) flows proximally from compartment 20 a to compartment 12 a—and, thereby, facilitates mixing of the flowing solution (e.g., 22) into the other solution (e.g., 14). And, by way of further example, it moves to a distal end of port 18′—e.g., as the solution (and/or other liquids, gasses or solids) flows proximally from compartment 12 a to compartment 20 a and, thereby, further facilitates mixing of the solutions.

In other embodiments, the internally-disposed diffuser 18 a′ can be constrained for more limited motion relative to the port 18′ (e.g., moving with fluid flow from a point at the proximal end to a point part way down to the distal end) and/or can be fixed, e.g., at a proximal end of the port, in order to facilitate such mixing. Regardless, the diffuser 18 a′ can be sized and/or disposed within the port 18′ so it is substantially entirely (if not completely so) embraced within the port 18′ and so that at the extremes of its motion (if at all) within the port, it does not extend substantially (if at all) beyond an end of the port, e.g., as shown (in the case of a floating diffuser 18 a′) in FIG. 18B.

As used here, the term “float” refers to motion of the diffuser 18 a′ in suspension within the entraining flow of solution, though, that motion may also be at least partially on a surface of that flowing solution.

Referring to FIG. 17B, the body of diffuser 18 a′ of the illustrated embodiment comprises multiple inlet/outlet apertures 18B′. These apertures may comprise passages extending through and/or surface indentations on the body of the diffuser 18 a′ oriented along an axis parallel (or otherwise) to the fluid flow path of the port 18 in which the diffuser 18 a′ is disposed. Three such apertures 18 b′ comprising surface indentations on the body of diffuser 18 a′ are shown in the illustrated embodiment, though other embodiments may utilize other numbers of apertures. The illustrated apertures may be disposed at angles Ω, as above, or otherwise, to effect dispersion of fluid flowing from vessel 21′ into vessel 12′ (and, more particularly, for example, upon expulsion into vessel 12′), e.g., in a pattern shown by the curved arrowhead lines in FIG. 17C solution (which presents a view of diffuser 18 a′ from the perspective line labelled “A” of FIG. 17B), though, the apertures of other embodiments may effect different dispersal patterns. A fourth aperture comprising a passage running centrally through the body of the diffuser 18 a′ is also provided in the illustrated embodiment.

As above, a temporary seal 24′ is provided in the fluid-transfer path defined by port 18′. This prevents contact between or mixing of the PD osmotic agent and the PD buffer agent, e.g., until after sterilization of the agents. The seal 24′ may be constructed and fabricated as discussed above, for example, in connection with FIG. 15, albeit in the embodiment of FIGS. 17A-17D and 18A-18B, it is disposed on the proximal end of port 18, as shown (rather than, for example, internal to the port 18).

Seal 24′ may be fabricated as discussed above in connection with FIG. 5 and, indeed, may be shaped as shown in that drawing—albeit, disposed at the proximal end of port 18, with the head 24 a′ and tail 24 b′ generally positioned as shown in FIGS. 17A-17D and 18A-18B and with flanges 24 d oriented in the reverse direction to insure that they secure the seal 24′ to the port when so positioned).

In the embodiment of FIGS. 17A-17D and 18A-18B, seal 24′ and port 18′ form a unitary structure (at least, prior to breaking of the frangible seal 24′) of the type shown, for example, in FIG. 17B. In the illustrated embodiment, the portion of that structure that makes up seal 24′ is generally elongate and has a generally spherical head portion 24 a′ formed on a generally cylindrical or conical tail portion 24 b′. The latter is bonded to the proximal end of port 18′, e.g., as shown, by way of frangible bond 24 e′. The tail portion 24 b′ can have a central throughway to insure fluid passage, if the seal 24′ breaks proximally of bond 24 e′, e.g., if the patient or care giver exerts a misdirected force on the structure when trying to break the seal 24′. Of course it will be appreciated that the seal/port structure may be constructed in other conformations consistent with the teachings hereof. The structure may be fabricated from polycarbonate, nylon, plastic, or other medical-grade material of the type used for the frangible seals, e.g., 62, 64, and it may be fabricated via injection molding or other suitable technique.

The portion of the aforementioned seal/port structure making up the port 18′ can comprise an aperture, tubing or other fluid transfer path suitable for integration with the seal 24′ and, in the embodiment of FIGS. 17A-17D and 18A-18B, for incorporation of internally-disposed diffuser 18 a′. One such port 18′ is shown in FIG. 17B. This is an elongate structure of generally cylindrical cross-section, with an inner diameter sized to permit the passage of solutions 14 and/or 22 (and/or other liquids, gasses or solids) between the compartments 12′, 21′ through and/or around diffuser 18 a′ in a manner that insures the desired dispersal pattern of such solution upon exit from the diffuser and seal/port structure. Although the seal/port structure of the illustrated embodiment is configured as shown in FIG. 17B, those of other embodiments may be configured otherwise consistent with the teachings hereof.

In addition to element(s) on its outer diameter such as flanges 18 e which assist in securing or anchoring the seal/port structure to the container 72, the seal/structure can include flanges, projections, indentations and/or other elements to insure that diffuser 18 a′ and/or seals 24′, 26′ do not block flow of solution into, through and/or out of seal/port structure after they (the seals) have been broken.

Thus, for example, the seal/port structure can include flanges 18 f on an inner diameter of its distal end, or otherwise, that are sized, positioned, and/or shaped to prevent the diffuser 18 a′ from exiting the seal/port structure during transport, storage, or use. Those flanges also prevent the diffuser from blocking flow through that structure, for example, when solution is flowing from compartment 12 to compartment 21.

This is illustrated in FIG. 18A, where aperture 18 a′ is shown entrained in fluid flow indicated by a distally-directed flow arrow, and where a distal end of the diffuser 18 a′ is butted against flanges 18 f, which prevent the diffuser from advancing toward the distal end of the structure closer than an offset, d, thereby, ensuring that there is adequate clearance between the outer surface of the diffuser 18 a′ and the inner surfaces of the seal/port structure for fluid egress (or ingress) from the distal end of the seal/port structure.

With further attention to FIGS. 17B and 18A, the flanges 18 f can be formed on tabs 18 g that, in the illustrated embodiment, comprise the distal end of the seal/port structure (though which may comprise separate structures in other embodiments). Those tabs 18 f facilitate manufacture by flexing outwardly to allow the diffuser 18 a to be inserted into the seal/port structure during assembly of the container system.

By way of further example, the proximal end of the seal/port structure can be formed or provided with flanges or other structure 18 h that, in addition to preventing the diffuser 18 a from exiting the seal/port structure, capture and align the diffuser with seal/port structure and with the overall direction of fluid flow, when solution is flowing from compartment 21 to compartment 12. This ensures that the fluid will be dispersed the aperture 18 a′ with a pattern as described above.

The flanges 18 f and/or tabs 18 g can also play a role in ensuring that the seal 26′, if it becomes fully detached, does not block the flow of solution through the seal/port structure after that seal is broken. Specifically, the flanges 18 f and/or tabs 18 g can be shaped to capture the broken and detached seal 26′ so that it does not block flow around gaps 18 j between the tabs and through seal/port structure, for example, when solution is flowing from compartment 2 to compartment 12. Such flow is better insured, in some embodiments, by inclusion of a through-passage 26 a defining a fluid flow via seal 26′, as shown.

The foregoing is illustrated in FIG. 18B, where diffuser 18 a′ and seal 26′ are shown entrained in fluid flow indicated by a proximally-directed flow arrow, and where (i) the proximal end of the aperture 18 a′ is captured by flanges or other structure 18 and, thereby, aligned with seal/port structure and with the overall direction of fluid flow, and (ii) the broken, detached seal 26′ is captured by flanges 18 f and/or tabs 18 g at an offset, d′, thereby, ensuring that there is adequate clearance between the outer surface of the seal 26′ and the inner surfaces of the seal/port structure for fluid enter from the distal end of the seal/port structure.

Though not illustrated here, the port 18′ can also include flanges or other structural elements to ensure that the seal 24′ does not block the flow of solution through the seal/port structure after that seal is broken. Such flanges or other structures can be constructed similarly to those discussed above, albeit on the proximal end of the port 18′, likewise ensuring that, if seal 24′ becomes engrained in a fluid flow of the type shown in FIG. 18A, it will be captured at an offset from the port 18′ sufficient to insure that there is adequate clearance between the outer surface of the seal 24′ and the inner surfaces of the port for fluid enter from the proximal end.

Referring to FIG. 9, an alternate arrangement of the structures shown in FIG. 1 can further insure that the seals are broken in an order that prevents fluid transfer to the catheter 28 (and any downstream equipment) prior to mixing of the PD agents. That drawing depicts container system 60 of the same general configuration as container system 10 of FIG. 1 (as indicated by like reference numerals), albeit with the second seal (element 26 of FIG. 1, element 62 of FIG. 9) disposed within vessel 20 (e.g., rather than between the distal port of that vessel 20 and the catheter 28) so as to inhibit its manipulation and breaking until seal 24 is broken and fluid (or other) pressure within the vessel is reduced.

As with seal 26, seal 62 is a frangible member that can be fabricated from nylon, plastic, or other medical-grade material, and that can be formed in the configurations discussed above in connection with seal 24 (and shown, for example, in FIG. 5). Moreover, like seal 26, seal 62 can be disposed between the distal port of the vessel 20 and the catheter 28 and affixed to (and/or formed integrally with) an interior fluid-transfer path of one or both of those.

Preferably, however, seal 62 is disposed so as to inhibit it from being manipulated (and, more significantly, broken) when vessel 20 contains its post-manufacture complement of PD buffer agent solution 22 (and/or other liquids, gasses or solids). In the embodiment of FIG. 9, this is achieved by extending the seal 62 within the vessel 20, e.g., in the manner shown in FIG. 9, so as to inhibit squeezing, twisting or other manipulation of vessel 20, catheter 28 or otherwise from breaking seal 62 prior to breaking of seal 24 and (i) expulsion of at least some of its post-manufacturing complement of PD buffering agent 22 (and/or other liquids, gasses or solids)—and, preferably, expulsion of at least 10%-30% and, still more preferably, at least 30%-50% and, yet still more preferably, at least 50%—of such agent (and/or other liquids, gasses or solids) and/or (ii) reduction of the turgidity or other pressure effected within the vessel 20 by that agent 22 (and/or other liquids, gasses or solids). Those skilled in the art will appreciate that configurations of seal 62 other than that shown in FIG. 9 can be employed to this same end, as well.

In some embodiments of the invention, the seals 24, 62, are colored differently to alert and remind the user of the proper order in which they are to be broken. Those skilled in the art will appreciate, of course, that coloration can be used in connection with other elements of the system 10, as well.

FIGS. 10A-10D depict utilization of PD system 60, including seal 62, in a manner according to the invention.

Initially, as shown in FIG. 10A, seals 24, 26 are unbroken and compartment 20 a contains its post-manufacture complement of buffer agent 22 (and/or other gasses, fluids, solids). Consistent with the discussion above, vessel 20 is under sufficient fluid (or other) pressure to inhibit squeezing, twisting or other manipulation of it sufficient to break seal 62.

Referring to FIGS. 10B-10C, seal 62 remains intact while the user breaks seal 24 (e.g., by bending the proximal end of vessel 20 relative to port 18) and compresses vessel 20 in order to expel buffer agent 22 for mixing with osmotic agent 14.

Referring to FIG. 10D, the user bends or otherwise manipulates vessel 20 in order to break seal 62, once the seal 24 has been broken and the pressure within vessel 20 has been reduced. Once that seal 62 is broken, the mixed PD constituents can pass to catheter 28 (and/or other downstream equipment).

Systems as described above (and below) can be used to contain, mix and dispense a variety of constitutes. In one embodiment, the first compartment houses a PD osmotic agent at physiological use concentrations, i.e., substantially at concentrations at which that agent will be introduced into the patient's abdomen. Those concentrations for example of dextrose is about 1.5%-4.25%, more preferably, about 2.0%-4.0% and, still more preferably, about 2.0%-3.0%. The PD osmotic agent is also at a physiologically low pH, i.e., a pH below that at which that agent will be introduced into the patient's abdomen, preferably, the pH is about 1.0-6.0 and, most preferably, about 1.0-3.0.

Examples of suitable PD osmotic agents include, but are not limited to, sugars such as glucose (e.g., dextrose), poly(glucose) (i.e., a polymer made from repeating glucose residues, e.g., icodextrin, made from repeating dextrose units), fructose, dextrans, polyanions, and the like. Other PD osmotic agents may be non-sugar osmotic agent that function as an equivalent could be a viable substitute, such as small amino acids.

In a preferred example, the PD osmotic agent is dextrose. The concentration of dextrose is about 1.5%-4.25%, more preferably, about 2.0%-4.0% and, still more preferably, about 2.0%-3.0%.

As used herein, “mEq/L” refers to the concentration of a particular PD solution component (solute) present in proportion to the amount of water present. More specifically, mEq/L refers to the number of milli-equivalents of solute per liter of water. Milli-equivalents per liter are calculated by multiplying the moles per liter of solute by the number of charged species (groups) per molecule of solute, which is then multiplied by a factor of 1,000. As an example, when 10 grams of citric acid are added to a liter of water, the citric acid is present at a concentration of 10 g/L. Anhydrous citric acid has a molecular weight of 192.12 g/mol; therefore, the number of moles per liter of citric acid, and consequently citrate anion (since there is one mole of citrate anion per mole of citric acid), is 10 g/L divided by 192.12 g/mol, which is 0.05 mol/L. Citrate anion has three negatively charged species in the form of carboxylate groups. Accordingly, the citrate concentration of 0.05 mol/L is multiplied by three and then by 1,000, in order to provide a concentration of citrate in terms of mEq/L, which in the present example is 156 mEq/L of citrate anion.

The same method of calculation can be used to determine the mEq/L of other agents such as lactate and dextrose. For example, 4.48 grams of sodium lactate (molecular weight of 112.1 gram/mol) per liter of water provides 40 mEq/L of sodium cations and 40 mEq/L of lactate anions. For dextrose, 42.5 grams of dextrose (molecular weight of 180.2 gram/mol) per liter of water provides 235.8 mEq/L of dextrose.

The PD osmotic agent can contain electrolytes, in addition to the osmotic agent. Suitable electrolytes may include, for example, sodium, potassium, calcium and magnesium. In the PD solution composition, the preferred concentration range for sodium is from about 100 to about 132 mEq/L. The preferred concentration range for potassium is less than about 3.50 mEq/L. The preferred concentration range for calcium is less than about 2.50 mEq/L. The preferred concentration range for magnesium is less than about 1.50 mEq/L.

The solution in the second container can be a concentrated agent and, specifically, in the illustrated embodiment (for example), a concentrated PD buffer solution. The term “concentrated” as used herein refers to an agent that is stronger than the chemically “Normal” concentration for that particular agent. The terms “Normal” and “Normal concentration” are used herein in the conventional sense of the chemical arts to refer to solutions having a concentration of 1 gram equivalent per liter of a solute. Thus, the Normal concentration of an ionic buffer agent is effectively equal to the molar concentration divided by the valence (the number of free or missing electrons) of the ion. For example, if a standard amount of a buffer agent is 60% (w/w), then 60 mls of that buffer agent would be added to one liter of water in order to obtain Normal concentration for that agent. In order to achieve a 10-fold increase in concentration (e.g., as in some embodiments of the invention), only 6 mls of the buffer is needed in one liter of solution.

The concentrated agent and, more specifically, the concentrated buffer utilized in systems and methods according to the invention can be of any concentration that is stronger than the chemically Normal concentration. For example, the concentrated buffer can be about 3-fold higher than Normal, 5-fold, 7-fold, 10-fold, 15-fold, and up to at least 50-fold higher than the Normal buffer. As those skilled in the art will appreciate, conventional, commercially available PD solutions, such as Deflex, by way of non-limiting example, are of chemically “Normal” concentration. Thus, the concentrated PD buffer agents utilized in embodiments of the present invention are of manifold increases in concentration relative to the commercial norm. The advantage of using concentrated buffers is that they can be stored and sterilized in small volume containers.

Alternatively, a sufficient quantity of buffer to produce a Normal concentration of a buffer upon mixing can be stored in a reduced volume. For example, a Normal amount of lactate buffer is typically 60% (w/w), i.e., 7.46 grams of sodium lactate buffer to one liter of solution. In this invention, the lactate buffer can be contained in the vessel 20 such that 7.46 grams of sodium lactate is contained in a vessel with a volumetric capacity of about 15 mls. The advantage of the invention is that the buffers can be contained and sterilized in small volume containers.

Examples of buffers include, but are not limited to, lactates, acetates, pyruvates, citrates, and the like. The lactate source may be any of lactic acid, sodium lactate, potassium lactate, calcium lactate, magnesium lactate, and the like. The acetate source may be any of acetic acid, sodium acetate, potassium acetate, calcium acetate, calcium acetate, magnesium acetate, and the like. Any or all of these chemicals are commercially available, in USP-grade if desired, from many chemical supply houses including, for example, Aldrich Chemical Co., Milwaukee Wis.

A preferred example of a PD buffer solution is a concentrated lactate buffer solution comprising lactate at a concentration of 20 miliequivalent per liter (mEq/l) to about 60 mEq/l, preferably a concentration of about 30 mEq/l to about 50 mEq/l, and most preferably, a concentration of 40 mEq/l. In addition, the lactate buffer solution may further comprise a bicarbonate at a concentration of about 5 mEq/l to about 10 mEq/l. A preferred buffer comprises 30-35 mEq/L of sodium lactate and 10-5.0 mEq/L of sodium bicarbonate.

The pH range of the PD osmotic agent solution is about 1.0-6.0 and, most preferably, between 1.0-3.0. The pH range of the PD buffer agent solution is about 8.0 to about 14.0, and, more preferably, a pH of about 9.0 to about 12 and, still more preferably, a pH of about 9.0 to about 10.0.

The different PD components can be dissolved in water that is essentially pyrogen-free and that at least meets the purity requirements established by United States Pharmacopia (USP)-grade for PD solutions.

A Normal PD solution typically comprises dextrose, sodium chloride, magnesium chloride and calcium chloride, sodium lactate, sodium hydroxide or hydrochloric acid added to adjust pH levels. The resulting pH of Normal PD solutions is about pH 5.0-6.0, which is less than optimum for blood, which has a pH of about 7.35 and 7.45. The Normal PD solutions often also contain GDPs. The seven commonly identified and published GDPs are acetaldehyde (AcA), 3-deoxglucosone (3-DG), 5-hydroxymethylfuraldehyde (5-HMF), glyoxal (Glx), methglyoxal (M-Glx), formaldehyde (FoA), and furaldehyde (FurA).

The systems and methods of the present invention provide PD solutions with reduced GDPs, as well as with more physiologically optimal concentrations and pH's. To this end, the PD osmotic agent solution and PD buffer agent are sterilized separately, thus, reducing the formation of degradation products that would otherwise result from the reaction of those agents at sterilization (or other high temperatures). The pH of the separate solutions is adjusted, moreover, in the illustrated embodiment, to further minimize GDP production during sterilization. That is to say the pH range of the PD osmotic agent solution is about 1.0-6.0 and, more preferably, between 1.0-3.0, while the pH range of the PD buffer agent solution is about 8.0 to about 14.0, and, more preferably, a pH of about 9.0 to about 12 and, still more preferably, a pH of about 9.0 to about 10.0. After sterilization, the buffer agent can be added to the osmotic agent solution, producing a mixed PD solution with a pH in the physiologically optimal range of about 5.0 to about 8.0 and, more preferably, about 6.0 to about 7.0, and, most preferably, about pH 7.2. As a result, systems and methods as described herein can provide PD solutions with an overall reduction in GDPs in the range of about 50% to about 80% compared with Normal PD solutions.

With continued reference to the drawings, in order to keep the PD osmotic and buffer agents separate prior to sterilization, vessels 12 and 20 are manufactured, shipped and stored with seals 24 and 26 intact. Those containers may be pre-assembled, e.g., so that they are available for use by a patient, health care provider or manufacturer in the configuration shown in FIG. 1 (not including attachment of catheter 28), or they may be manufactured, shipped and stored as kits, e.g., with the vessels 12 and 20 filled with their respective PD agents, but in unassembled form. The seal 24 may also be broken after sterilization at the time of manufacture.

Regardless, the vessels 12, 20 are sterilized before the seal 24 is broken and, therefore, before their respective contents have had a chance to mix. This is shown in step 30 of FIG. 2, which is a flow chart depicting a sequence for sterilizing and administering a PD solution according to the invention. This sterilization, which can be performed by the manufacturer and/or the health care provider, is achieved by steam-sterilization or other such conventional methods known in the art. Sterilization times and temperatures/pressures are in accord with those appropriate for the separated agents contained in vessels 12, 20, not reduced times and temperatures/pressures which might otherwise be necessary to prevent GDP build-up in sterilization of the combined components.

With continued reference to FIG. 2, step 32, following sterilization, seal 24 is broken (e.g., by squeezing and/or twisting of vessel 20 and/or port 18) to permit mixing of the PD buffer agent with the PD osmotic agent. The agents can be mixed by shaking, kneading or other action on the vessels 12, 20. See step 34. Thereafter, the solution is ready for administration—pending, for example, warming or other steps necessary for patient comfort or well being. To this end, seal 26 is broken, e.g., by squeezing or twisting of the distal port of vessel 20 and/or its interface with catheter 28. See step 36. Where a protective member (such as cover 52) is present, step 36 can further include the step of moving the protective member to allow access to, and breaking of, seal 26. Once seal 26 is broken, the PD solution can exit from the port into the catheter (and any downstream equipment) and, finally, to a patient. See step 38.

FIG. 3 depicts system 40 according to a further embodiment of the invention generally constructed and utilized (as indicated by like reference numerals) as system 10, described above. Differences in construction and utilization are discussed in the text that follows and are evident in the drawings.

Vessel 42 of system 40 comprises compartment 42 a for, by way of example, PD buffer agent solution 22, as generally described above. Compartment 42 a and vessel 42 are collapsible—i.e., they are configured such that force applied thereto, e.g., by a patient, health care provider or other, causes the volume of compartment 42 a to at least temporarily decrease so as to expel fluid contained therein. To this end, in the illustrated embodiment, vessel 42 has fan-fold walls, or bellows, along an axis aligned with a direction of fluid expulsion—here, along the fluid transfer path between vessel 42 and vessel 12. Other embodiments may utilize walls of other construction to facilitate collapse along the same or other axes. Regardless, those walls are preferably sufficiently durable to prevent leakage, e.g., so that after fluid expulsion, the compartment 42 a can form part of a fluid transfer path between the compartment 12 a and the patient's peritoneal cavity.

Illustrated vessel 42 may be fabricated from PVC, polyolefin, polypropylene, rubber and/or other medical grade materials suitable for forming a collapsible container as described herein. As with vessel 20 (FIG. 1), above, vessel 42 can be formed, e.g., by blow molding, dip-forming, or otherwise.

As above, seal 24 is adapted to prevent fluid transfer (or other contact) between the PD agents contained in the compartments during manufacture, transport, storage and sterilization of system 40, yet, to permit such fluid transfer upon squeezing, twisting or other manipulation of vessel 42 and/or port 18 by a patient, health care provider, or manufacturer, e.g., following sterilization.

Like seal 26 of systems 10 and 50 (FIGS. 1 and 6), seal 44 of system 40 is adapted to prevent fluid transfer to the catheter 28 (and any downstream equipment) prior to sterilization and mixing of the PD agents. However, unlike seal 26, seal 44 (which, too, is disposed at the distal port of the vessel 42) is broken by a further member 46 that is disposed in compartment 42 a and that pierces, cuts or otherwise breaks seal 44 when the vessel 42 and compartment 42 a have been compressed sufficiently to insure expulsion of the fluid 22 into compartment 12 a.

Seal 44 can be formed of PVC, polyolefin, polypropylene, rubber and/or other medical grade materials suitable for preventing fluid transfer, e.g., during manufacture, shipping, storage, sterilization, but susceptible to being broken, e.g., by member 46 as described here, following sterilization and mixing of the agents 14, 22.

In the illustrated embodiment, member 46 is depicted as a bayonet, though in other embodiments it may be of another shape. It can be constructed of the same materials utilized, e.g., for element 24. Member 46 can be formed near the proximal port of vessel 42 (e.g., opposite seal 24) and affixed to (and/or formed integrally with) an interior fluid-transfer path between the vessels, as shown, though in other embodiments it may be disposed elsewhere, e.g., preferably so that it breaks member 44 upon sufficient compression of vessel 42 and compartment 42 a. To this end, in the illustration, member 46 is of such length that its tip (for piercing seal 44) is disposed approximately 40% from the proximal end of compartment 42 a. In other embodiments, the member may be of other lengths, depending upon the compressibility of compartment 42 a and on the desired degree of expulsion of fluid 22 from compartment 42 a to compartment 12 a prior to piercing of seal 44.

As above, the container system 40 permits the PD osmotic agent solution and PD buffer agent to be sterilized separately, thus, reducing the formation of degradation products that would otherwise result from the reaction of the osmotic agent with the buffer agent at high temperature. To this end, the vessels 12 and 42 are manufactured, shipped and stored with seals 24 and 44 intact. Those containers may be pre-assembled, e.g., so that they are available for use by a patient or health care provider in the configuration shown in FIG. 3 (not including attachment of catheter 28), or they may be manufactured, shipped and stored as kits, e.g., with the vessels 12 and 42 filled with their respective PD agents, but in unassembled form. As noted above, the seal 24 may also be broken after sterilization at the time of manufacture.

Regardless, as above, the vessels 12, 42 are sterilized before the seal 24 is broken and, therefore, before their respective contents have had a chance to mix. Such sterilization may be accomplished as described above, e.g., in connection with step 30 of FIG. 2.

Following sterilization, a factory worker, health care provider, a patient, or other, breaks seal 24 (e.g., by squeezing and/or twisting of vessel 42 and/or port 18); see, FIG. 4A. He or she then compresses (or collapses) vessel 42 to expel agent 22 from compartment 42 a into compartment 12 a, thereby, facilitating its mixing with agent 14; see, FIG. 4B.

The factory worker, health care provider, patient or other continues compressing (or collapsing) vessel 42 until the tip of member 46 contacts and breaks seal 44; see, FIG. 4C. This allows the PD solution to exit from the port into the catheter (and any downstream equipment) and, finally, to a patient.

It will be appreciated that systems and methods according to the invention are applicable to a range of peritoneal dialysis applications and other medical applications in which at least one agent (or combination of agents) requires separate sterilization prior to combination with another agent (or combination thereof). According to conventional practice, such agents are sometimes combined prior to sterilization or, if combined after sterilization, for example, by injecting one of them into a medication port of a container that holds the other agent. The former increases risk of degradation of the agents. The latter increases the risk to health care personnel and/or the patient. Systems and methods of the invention avoid these risks and other shortcomings of the prior art by allowing the agent(s) to be sterilized separately and, then, combined, e.g., without the use of needles or other mechanisms that are expensive, unwieldy, and/or place the agent(s), health care personnel and/or patients at risk.

Another advantage of systems and methods of the invention, is that depending on the requirements of the agent that will be added to the medical solution, the second vessel can be coated with materials that maintain the shelf life and/or stability of the agent or additive. Examples of additives that can be administered with this invention are amino acids, proteins, heparin, and vitamins.

As evident in the examples below, systems and method of the invention have been used to prepare PD solutions with reduced GDPs and a more physiologically optimal pH levels.

TABLE 1 Samples Preparation pH mL of 1.0M Adjusted HCI per Liter Label To of Solution WFI Glucose CaCl₂*2H₂O MgCl₂*2H₂O NaCl 1 3.0 1.37 80 L 3,400 g 14.72 g 4.072 g 430.16 g 2 4.0 0.37 3 4.5 0.27 4 5.2 0.18 Buffer Straight Lactate Syrup up to 1000 g in a 1-Liter Bag

Table 1 shows sample preparations with the PD solutions constituents at different pH values. The sample labeled “Buffer” has concentrated lactate buffer solution added to it.

TABLE 2 GDPs results from HPLC Analysis Cl 3-DG AcA 5-HMF Gix M-Gix FoA FurA Label pH (mEq/L) (μmol/L) (μmol/L) (μmol/L) (μmol/L) (μmol/L) (μmol/L) (μmol/L) Buffer 8.1 — ND 15 ND ND ND 3 ND 1-A 3.0 — 37 ND ND ND 7 ND ND 1-B 3.0 — 119 ND 18 ND 8 ND ND 1-C 3.0 — 115 2 23 ND 7 ND ND 1-D 3.0 — 119 1 22 ND 9 ND ND 2-A 4.0 — 65 ND ND ND 9 ND ND 2-B 4.0 — 299 ND 39 ND 8 1 ND 2-C 4.0 — 299 ND 38 ND 13 ND ND 2-D 4.0 — 248 ND 34 0.2 8 ND ND 3-A 4.7 — 91 ND ND ND 9 ND ND 3-B 4.4 — 526 0.1 45 0.5 9 ND ND 3-C 4.4 — 532 ND 46 ND 9 ND ND 3-D 4.4 — 513 ND 46 0.7 14 ND ND 4-A 5.5 — 112 ND ND 0.2 7 ND ND 4-B 4.5 — 699 ND 54 0.7 8 ND ND 4-C 4.5 — 653 ND 51 1.6 11 ND ND 4-D 4.5 — 649 0.2 44 0.6 8 3 ND 1-A (buffered) 5.3 95.5 45 6 ND ND 9 ND ND 1-B (buffered) 5.3 95.6 131 16 26 ND 8 ND ND 1-C (buffered) 5.3 94.8 128 15 25 ND 9 ND ND 1-D (buffered) 5.3 95.4 134 15 25 ND 10 ND ND 2-A (buffered) 6.1 95.7 90 6 ND ND 10 ND ND 2-B (buffered) 6.1 95.2 316 20 39 ND 7 ND ND 2-C (buffered) 6.1 95.3 307 19 40 ND 11 ND ND 2-D (buffered) 6.1 95.0 303 2 35 ND 9 ND ND 3-A (buffered) 6.4 95.1 95 10 ND 0.5 11 ND ND 3-B (buffered) 6.3 95.3 570 18 46 0.3 7 ND ND 3-C (buffered) 6.3 95.1 537 3 45 0.5 13 ND ND 3-D (buffered) 6.3 95.4 560 20 45 ND 7 ND ND 4-A (buffered) 6.6 95.4 121 7 ND 0.4 10 ND ND 4-B (buffered) 6.3 95.0 650 16 52 ND 9 ND ND 4-C (buffered) 6.3 95.8 668 3 50 1.7 13 ND ND 4-D (buffered) 6.3 96.2 685 19 50 0.7 10 4 ND 4.25% Delfex 5.2 95 348 323 38 4   25 12  ND 4.25% Balance 7.0 — 175 49 12 4   14 4 ND

Table 2 shows the results of HPLC analysis of the samples to examine the various degradation products. The seven degradation products that were analyzed are as follows: acetaldehyde (AcA), 3-deoxglucosone (3-DG), 5-hydroxymethylfuraldehyde (5-HMF), glyoxal (Gix), methglyoxal (M-Gix), formaldehyde (FoA), and furaldehyde (FurA). The data from Table 2 shows that GDPs formation around pH 3.0 is the lowest among the solutions prepared and the Normal/commercial products. Sodium lactate as a buffer agent in PD solutions results in acetaldehyde (AcA) formation (See column entitled “pH” in Table 2). The results also demonstrate the effectiveness of reducing AcA formation by separating sodium lactate from the rest of the PD solution for steam sterilization. By adding sodium lactate buffer solution to the main PD solution at pH 3.0 (group 1), the resulting mixed PD solution has a pH of 5.2, which is the same as Normal PD solutions (referred to as “Delflex” in Table 2), but with significantly reduced GDPs than Normal PD solutions. This data demonstrates that reduced GDPs are obtained under current formulation and pH levels using the system of the invention. The data also shows that PD formulations with reduced GDPs are obtained at a physiological of around pH 7.0 (Table 4). Thus, the systems and methods of the invention provide significantly reduce GDPs in PD solutions that contain dextrose as an osmotic agent and sodium lactate as buffer.

In some embodiments of the invention, the PD solutions are produced with reduced GDPs by using a buffer solution with a bicarbonate (e.g., sodium bicarbonate). The first vessel 12 contains a PD osmotic agent solution with dextrose, sodium chloride, magnesium chloride, calcium chloride, and hydrochloric acid to adjust the pH to 3.0. In one example, the vessel 20 is filled with a concentrated PD lactate buffer solution with lactate only, adjusted to a pH of about 10.0 to about 12.0. Sodium hydroxide can be used to adjust the pH of the lactate buffer. A suitable concentration of lactate buffer is 40 mEq/l lactate buffer. In another example, the second vessel 20 is filled with a concentrated PD lactate buffer solution comprising a bicarbonate buffer, adjusted to a pH of about 8.0 to about 9.0. Suitable concentrations are, 37 mEq/l lactate buffer with 3 mEq/l bicarbonate buffer.

The results obtained by using the methods and compositions of the present invention using buffer solutions are summarized in Tables 3 and 4.

TABLE 3 Formulation Comparison as Delivered to a Patient FORMULATION, LowCA Bubble PVC Product (mini-bag) bicarb or total Design with Vol Soln lactate NaOH buffer Na Cl Mg Dextrose Bubble [m/l] pH [mEq/l] [mEq/l] [mEq/l] [mEq/l] [mEq/l] [mEq/l] [%] 1 Neutral pH PD 6.7 7.4 38.04 1.06 of 40 132 95 0.5 1.50% solution, lactate/ NaOH 4.25% NaOH in bubble 2 Neutral pH PD 10 7.4 37 3 of sodium 40 132 95 0.5 1.50% solution; lactate/ biacarbonate 4.25% bicarb buffer in bubble 3 Delflex (current NA 5.3 40 0 40 132 95 0.5 1.50% Product as 4.25% reference) 4 Balance (as NA 7.0 40 0 40 134 101.5 1.0 1.50% reference only) 4.25%

Table 4 shows the results of an average of 3 samples. The concentrated PD lactate buffer was mixed with PVC bag contents containing the PD osmotic agent solution post sterilization. After combining the PD lactate buffer with the PD osmotic agent buffer, the resulting PD solution was examined and had a significantly reduced amount of AcA compared with the existing commercially available PD solutions referred to as “Deflex” and “Balance.” Also, by maintaining the pH of the PD osmotic solution at 3.0 and then by adding concentrated PD lactate buffer at a pH of 10.0 to 12.0, the final pH of the resulting PD solution was at a more physiologically optimal pH of 7.2 (Table 4).

TABLE 4 GDP Results GDPs Delflex Balance pH 3 pH 3 (μ mole/L) (4.25%) (4.25%) Dextrose-side Dextrose-side pH (Final, Mixed) 5.2 6.9 53 7.1 Buffer Lactate Lac/bic Lactate only Lactate/NaOH 3-DG 348 175 131 106 AcA 323 49 15 13 5-HMF 38 12 25 28 Glx 4 4 ND 1 M-Glx 25 14 9 8 FoA 12 2 ND 1 Reduction Ratio 0% 65% 76% 80% (%)

Collectively, these demonstrate that by sterilizing a concentrated PD lactate buffer separately from the PD osmotic agent, and then adding the concentrated PD lactate buffer just before use, the amount of GDPs are significantly reduced. In addition, the resulting PD solution has a near neutral pH of about 7.4 optimized for peritoneal dialysis. Furthermore, the concentrated PD lactate buffer may also contain bicarbonate. When the PD lactate-bicarbonate buffer was added to the PD osmotic agent solution, the resulting PD solution also had significantly reduced GDPs, and a near neutral pH of about 7.4.

Described above are systems and method meeting the desired objects, among others. It will be appreciated that the embodiments illustrated and described herein are merely examples of the invention and that other embodiments, incorporating changes thereto, fall within the scope of the invention. Thus, by way of non-limiting example, it will be appreciated that although the first and second agent-containing compartments of the illustrated embodiments are shown as carrying agents of medical PD solutions), in other embodiments those compartments may contain agents of other medical or non=medical solutions. Moreover, it will be appreciated that, by way of further non-limiting example, although the text above describes breaking of the temporary seals (e.g., seals 24, 26, 44, 62) by manual manipulation, e.g., of the vessel 20, other embodiments may be adapted for breaking of those seals by automated apparatus (e.g., manipulation of the vessel or mini-tube 20 by robotic equipment or otherwise). In this context, what we claim is: 

1. A container system for medical solutions, comprising A. a first compartment that contains a first medical solution, B. a second compartment that contains a second medical solution, the second compartment being fluidly couplable with the first compartment via a fluid pathway-defining structure (hereinafter, “port”), C. a diffuser that is disposed within and movable relative to the port.
 2. The container system of claim 1, wherein the diffuser facilitates mixing of the first and second medical solutions.
 3. The container system of claim 1, wherein the first medical solution comprises a peritoneal dialysis (“PD”) osmotic agent and wherein the second medical solution comprises a PD buffer agent.
 4. The container system of claim 1, wherein the diffuser comprises a body that floats within the port, moving therein depending on a direction of solution flow through the port.
 5. The container system of claim 5, wherein the diffuser moves from one end of the port to another end of the port, and/or to from points there between, depending on a direction of solution flow through the structure.
 6. The container system of claim 1, wherein the diffuser is enclosed at least substantially entirely within the port.
 7. The container system of claim 6, wherein the diffuser is enclosed within the port such that at extremes of its motion within the port, the diffuser does not protrude substantially beyond an end of the port.
 8. The container system of claim 1, wherein the diffuser comprises one or more apertures to effect dispersion of any of the first and second medical solutions flowing from one of the compartments into the other compartment.
 9. The container system of claim 9, wherein the one or more apertures effect said dispersion on expulsion of any of said first and second medical solutions into said other compartment.
 10. The container system of claim 9, wherein one or more of the apertures comprise passages extending any of through the body of and along a surface of the diffuser.
 11. The container system of claim 10, wherein one of more of said apertures are oriented along an axis parallel to a fluid flow path of the port.
 12. A multiple chamber vessel for peritoneal dialysis (PD) solutions, comprising A. a first compartment of a contains a PD osmotic agent, B. a second compartment that contains a PD buffer agent, the second compartment being fluidly couplable with the first compartment via a fluid pathway-defining structure (hereinafter, “port”), C. a diffuser that is disposed within and movable relative to the port.
 13. The multiple chamber vessel of claim 12 formed such that at least one of the compartments to be bent, twisted, squeezed, folded and/or otherwise manipulated at least partially independently of the other compartment.
 14. The multiple chamber vessel of claim 12, wherein portions of the vessel in which the respective compartments are formed are at least partially separable from one another.
 15. The multiple chamber vessel of claim 14, wherein portions of the vessel in which the respective compartments are formed so that one portion can be folded and its respective compartment squeezed without substantially folding the other portion and squeezing its respective compartment.
 16. The multiple chamber vessel of claim 12, wherein the port includes a first frangible seal to prevent contact between the PD osmotic agent and the PD buffer agent.
 17. The multiple chamber vessel of claim 16, wherein the first frangible seal is adapted to be broken by a patient or health care provider to permit the agents to mix.
 18. The multiple chamber vessel of claim 16, comprising a second frangible seal that prevents fluid transfer between the second compartment and an outlet fluid pathway of the vessel.
 19. The multiple chamber vessel of claim 18, comprising a protective structure that deters breaking of the second seal prior to breaking of the first seal.
 20. The multiple chamber vessel of claim 19, wherein the protective structure includes an opening arranged to slide over at least a portion of the vessel forming the second compartment only if that vessel is at least partially folded.
 21. A container system for medical solutions, comprising A. a first compartment that contains a first medical solution, B. a second compartment that contains a second medical solution, the second compartment being fluidly couplable with the first compartment via a fluid pathway-defining structure (hereinafter, “port”), C. a diffuser that is disposed within and movable relative to the port, D. wherein the port includes one or more structural elements that prevent the diffuser from obstructing flow of medical solution into, through and/or out of the port.
 22. The container system of claim 21, wherein the one or more structural elements are disposed at an end of of the port and on an inner diameter thereof.
 23. The container system of claim 22, wherein the one or more structural elements are any of sized and shaped to prevent the diffuser from advancing toward an end of the structure closer than an offset that ensures adequate clearance for fluid passage to/from that end.
 24. The container system of claim 21, in which the port includes one or more tabs that flex to allow the diffuser to be inserted into the port.
 25. A multiple chamber vessel for peritoneal dialysis (PD) solutions, comprising A. a first compartment that contains a PD osmotic agent, B. a second compartment that contains a PD buffer agent, the second compartment being fluidly couplable with the first compartment via a fluid pathway-defining structure (hereinafter, “port”), C. wherein the port includes a first frangible seal to prevent contact between the PD osmotic agent and the PD buffer agent, D. a second frangible seal that prevents fluid transfer between the second compartment and an outlet fluid pathway of the vessel, E. wherein the port includes one or more structural elements that prevent at least one of the first and second seals obstructing flow of PD agent into, through and/or out of the port after that respective seal is broken.
 26. The multiple chamber vessel of claim 25, comprising a diffuser that is disposed within and movable relative to the port.
 27. The multiple chamber vessel of claim 26, wherein the port includes one or more structural elements that prevent the diffuser from obstructing flow of PD agent into, through and/or out of the port. 